December weather forecastReilly Heights, CA
December
Weather in December
December, the first month of the winter in Reilly Heights, is still a cool month, with an average temperature fluctuating between 37.4°F (3°C) and 53.6°F (12°C).Temperature
The lowest temperatures are recorded in December, with averages reaching a high of 53.6°F (12°C) and a low of 37.4°F (3°C).Humidity
In Reilly Heights, the average relative humidity in December is 76%.Rainfall
The wettest months are February and December, with an average 3.11" (79mm) of rainfall.Snowfall
January, March through December are months without snowfall.Daylight
December has the shortest days of the year, with an average of 9h and 30min of daylight.On the first day of the month, sunrise is at 7:14 am and sunset at 4:51 pm. On the last day of December, sunrise is at 7:33 am and sunset at 5:01 pm PST.
Sunshine
December has the least sunshine of the year, with an average of 5.3h of sunshine.UV index
In December, the average daily maximum UV index is 3. A UV Index value of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for the ordinary person.Note: The maximum daily UV index of 3 in December converts into the following recommendations:
Ensure safety - Sun damage prevention is strongly urged. Avoiding direct sun during mid-day hours can prevent harmful UV radiation exposure. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Reilly Heights, CA
- Average high temperature in December: 53.6°F
The warmest month (with the highest average high temperature) is July (85.3°F).
The month with the lowest average high temperature is December (53.6°F).
- Average low temperature in December: 37.4°F
The month with the highest average low temperature is July (53.6°F).
The coldest month (with the lowest average low temperature) is December (37.4°F).
Average pressure in December
Reilly Heights, CA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).
Average wind speed in December
Reilly Heights, CA
- Average wind speed in December: 4.5mph
The windiest months (with the highest average wind speed) are April, May and June (5.5mph).
The calmest month (with the lowest average wind speed) is November (4.2mph).
Average humidity in December
Reilly Heights, CA
- Average humidity in December: 76%
The month with the highest relative humidity is March (79%).
The months with the lowest relative humidity are July and September (58%).
Average rainfall in December
Reilly Heights, CA
- Average rainfall in December: 3.11"
The wettest months (with the highest rainfall) are February and December (3.11").
The driest months (with the least rainfall) are July and August (0.08").
Average rainfall days in December
Reilly Heights, CA
- Average rainfall days in December: 12.5 days
The month with the highest number of rainy days is March (14.3 days).
The month with the least rainy days is August (1.3 days).
Average snowfall in December
Reilly Heights, CA
- Average snowfall in December: 0"
The month with the highest snowfall is February (0.04").
The months with the least snowfall are January, March, April, May, June, July, August, September, October, November and December (0").
Average snowfall days in December
Reilly Heights, CA
- Average snowfall days in December: 0 days
The month with the highest number of snowfall days is February (0.3 days).
The months with the least snowfall days are January, March, April, May, June, July, August, September, October, November and December (0 days).
Average daylight in December /
Average sunshine in December
Reilly Heights, CA
- Average daylight in December: 9h and 30min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 5h and 18min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).
Average sunshine days in December
Reilly Heights, CA
- Average sunshine days in December: 17.6 days
The month with the most sunshine days is July (28.5 days).
The month with the least sunshine days is March (15.9 days).
Average UV index in December
Reilly Heights, CA
- Average UV index in December: 3
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are February and November (UV index 2).
Average cloud cover in December
Reilly Heights, CA
- Average cloud cover in December: 42
The month with the most cloud cover is March (Cloud cover 45).
The month with the least cloud cover is August (Cloud cover 6).
Average visibility in December
Reilly Heights, CA
- Average visibility in December: 5mi
The months with the highest visibility are February, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, March and December (5mi).
